class

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A set, collection, group, or configuration containing members regarded as having certain attributes or traits in common; a kind or category.
• noun A division based on quality, rank, or grade, as.
• noun A grade of mail.
• noun A quality of accommodation on public transport.
• noun A social stratum whose members share certain economic, social, or cultural characteristics.
• noun Social rank or caste, especially high rank.
• noun Informal Elegance of style, taste, and manner.
• noun A group of students who are taught together, usually at a regularly scheduled time and in the same subject.
• noun The period during which such a group meets.
• noun The subject material taught to or studied by such a group.
• noun A group of students or alumni who have the same year of graduation.
• noun Biology A taxonomic category ranking below a phylum or division and above an order.
• noun Statistics An interval in a frequency distribution.
• noun Linguistics A group of words belonging to the same grammatical category that share a particular set of morphological properties, such as a set of inflections.
• noun Mathematics A collection of sets whose members share a specified property.
• transitive verb To arrange, group, or rate according to qualities or characteristics; assign to a class; classify.

from The Century Dictionary.

• An abbreviation of classic or classical
• of classification.
• noun In petrography, in the quantitative classification of igneous rocks (see rock), the highest division.
• noun In shipbuilding, the indication of the character, style of construction, and quality of workmanship and outfit of a merchant vessel, as determined by the rules and inspection of a registration society. The class to which a vessel is assigned is indicated in the register of each society by a conventional character such as 100A, 90A, etc. See A, 2 .
• noun the indication of the size and power of any given type of war-ship: as, a first-class battle-ship, a first-, second-, or third-class cruiser, etc.
• noun In crystallog., one of the thirty-two groups in which crystals are divided in accordance with the special type of symmetry which characterizes them. See symmetry.
• In shipbuilding, to assign to a class of a registration society, such as Lloyd's: said of a merchant vessel. A vessel not classed is one which has not been inspected and assigned a class by any registration society, or the classification of which has been refused for some reason, not necessarily involving deterioration or inferior quality.
• To be assigned to a class. See I., 3.
• noun In anc. hist., one of the five divisions of the Roman citizens made, according to their wealth, by Servius Tullius, for purposes of taxation: a sixth division comprised those whose possessions fell below the minimum of the census.
• noun An order or rank of persons; a number of persons having certain characteristics in common, as equality in rank, intellectual influence, education, property, occupation, habits of life, etc.
• noun Any body of persons grouped together by particular circumstances or for particular reasons.
• noun A number of objects distinguished by common characters from all others, and regarded as a collective unit or group; a collection capable of a general definition; a kind.
• noun In natural history, a group of plants or animals next in rank above the order or superorder, and commonly formed by the union of several orders or superorders: but it may be represented by a single species. See classification.
• noun In geometry, the degree of a locus of planes; a division of algebraical loci bearing an ordinal number showing how many planes there are incident to the locus and passing through each line of Space.
• To arrange in a class or classes; rank together; regard as constituting a class; refer to a class or group; classify; range.
• To place in ranks or divisions, as students that are pursuing the same studies; form into a class or classes, as in an educational institution.
• To be arranged or classed.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To be grouped or classed.
• adjective informal exhibiting refinement and high character. Opposite of low-class
• transitive verb To arrange in classes; to classify or refer to some class.
• transitive verb To divide into classes, as students; to form into, or place in, a class or classes.
• noun A group of individuals ranked together as possessing common characteristics.
• noun A number of students in a school or college, of the same standing, or pursuing the same studies.
• noun A comprehensive division of animate or inanimate objects, grouped together on account of their common characteristics, in any classification in natural science, and subdivided into orders, families, tribes, genera, etc.
• noun A set; a kind or description, species or variety.
• noun (Methodist Church) One of the sections into which a church or congregation is divided, and which is under the supervision of a class leader.
• noun One session of formal instruction in which one or more teachers instruct a group on some subject. The class may be one of a course of classes, or a single special session.
• noun A high degree of elegance, in dress or behavior; the quality of bearing oneself with dignity, grace, and social adeptness.
• noun (Math.) the kind of a curve as expressed by the number of tangents that can be drawn from any point to the curve. A circle is of the second class.
• noun (Methodist Church) a meeting of a class under the charge of a class leader, for counsel and relegious instruction.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun countable A group, collection, category or set sharing characteristics or attributes.